1. Field of the Invention
The purpose of the present invention is a filter with an impeller belonging to the field of equipment for separating fluids or liquids and solids in suspension, which received original construction for providing controlled turbulence for solids, obtained with an impeller with adequate characteristics for impelling the liquid to be filtrated inside a filtrating sleeve and according to a vortex movement.
2. Description of Relevant Art
A filter for separating liquids and solids of products in suspension is already known such as, for example, fruit juices in general and others. The filter comprises a filter body, an end of which provides a feeding inlet for the product to be filtrated. The middle portion of said body contains a filtrating element, and a lower outlet for the filtrated material. The opposite end of said filter body provides an outlet for solids. The filter body is mounted on a carrying structure through articulations and an adjustable inclination device. The filtrating element comprises a filtrating sleeve, the inlet of which is close to the inlet of the filter body. The middle portion said sleeve shelters a portion of a winged impeller and the other end of the filtrating sleeve, is located at the outlet for solids of the filter body. The winged impeller is subject to an actuating assembly external to the filter body.
In the usual form of construction for this type of filter, its impeller is formed by two portions of different wings defining two phases, namely: an inlet phase located close to the inlet end of the filtrating sleeve, and consisting of a propeller to give an axial movement to the product to be filtrated; and a processing phase consisting of flat radial blades impelling the liquid radially against the filtrating sleeve. Completing the impeller, a self-cleaning device is provided for the filtrating sleeve, comprising, for example, a helicoidally wound-up thread or wire around the radial processing blades close to the inner face of the filtrating sleeve which mechanically drags the solid material retained in the sleeve towards the outlet thereof.
With reference to the utilization of such filter, it has many problems. One first problem concerns the fact that the liquid to be filtrated suffers a quick change of direction between the phases for the inlet and processing of the impeller--it passes from axial movement to radial movement--and is also subject to impacts against the inner surfaces of the impeller, thus causing a great loss of axial hydrodynamic impulse. The loss of impulse causes the liquid to be concentrated as it goes through the initial region of the filtrating sleeve. This brings about differentiated efforts to the sleeve and, depending on the material of its construction, there may occur elastic deformations to the detriment of a good performance. Only a small part of the filtrating area of the sleeve is effectively used in the processing of the material.
Another problem arising from the usual filter as described above, concerns the fact that the mechanical self-cleaning device, depending on the concentration level of the solid material suspended in the liquid, causes squeezing and crushing of the solids against the filtrating sleeve. This may cause chockings and wear and tear on the screen which are harmful to it and/or a certain malfunction of the equipment, thus making it operate rather forcedly.